KIEV, Feb 19 (Reuters) - Ukrainian President Viktor Yanukovich appointed a new head of the armed forces general staff on Wednesday after street clashes between protesters and police in which at least 26 people have been killed since Tuesday.

He named Admiral Yury Ilyin, who had been head of the navy, to succeed Colonel-General Volodymyr Zamana. The army officer has now been appointed a member of the National Security and Defence Council, a body which reports to the president.

The presidential decree gave no explanation for the change in personnel, nor for the timing of the appointments.

Earlier on Wednesday, the defence ministry said the armed forces might take part in a countrywide anti-terrorist operation organised by the state security service. It has previously said that troops could only be used domestically if a state of emergency were declared. (Reporting By Richard Balmforth; Editing by Alastair Macdonald)